The embodiment relates to a configuration of a communication terminal, and more particularly, to an antenna apparatus and a feeding structure thereof.
Generally, a communication terminal includes an antenna apparatus to transmit/receive an electromagnetic wave. The antenna apparatus resonates at a specific frequency band to transmit/receive an electromagnetic wave having a corresponding frequency band. In this case, when the antenna apparatus resonates at the corresponding frequency band, impedance has an imaginary number. Further, an S parameter with respect to the antenna apparatus is rapidly reduced at the corresponding frequency band.
In this regard, the antenna apparatus includes a conducting wire having an electric length of λ/2 with respect to a wavelength λ corresponding to the desired frequency band. The antenna apparatus transmits the electromagnetic wave through the conducting wire and the electromagnetic wave forms a standing wave in the conducting wire so that resonance is achieved in the antenna apparatus. In this case, the antenna apparatus may include a plurality of conductive waves having mutually different lengths to expand a resonance frequency band.
However, since an electric length of the conducting wire in the above antenna apparatus is determined depending on a resonance frequency band, the size of the antenna apparatus is determined depending on the resonance frequency band. Accordingly, as a resonance frequency band to be realized is gradually reduced in the antenna apparatus, the size of the antenna apparatus becomes enlarged. The above problem may become serious as the number of conducting wires in the antenna apparatus is increased. That is, as the resonance frequency band is expanded in the antenna apparatus, the size of the antenna apparatus may become enlarged.